* {
  margin: 0;
  padding: 0;
}
body {
  position: relative;
}
header {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}
header > a {
  margin-left: 20px;
}

.table_fu {
  /* position: absolute; */
  display: flex;
  margin-top: 50px;
  /* 垂直居中 */
  align-items: center;
  justify-content: center;
  height: 100vh;
}
table {
  border: 1px solid #ccc;
  /* 选择表的边框模型。语法:collapse | separate */
  border-collapse: collapse;
  /* 指定字素簇之间的最小、最大和最佳间距。 */
  letter-spacing: 1px;
  text-align: center;
}
thead,
tfoot {
  background-color: #3f87a6;
  color: #fff;
}
tbody {
  background-color: #e4f0f5;
}
tr,
th {
  width: 150px;
  height: 30px;
}
